K-Bracing
K-Bracing
(OP)
Is it a right assumption to model the k-bracing in a frame as tension only members? I've entered a frame into RISA and specified the k-braces to be tension only members. In the results it shows the members taking compression. Should I model the bracing as compression members?






RE: K-Bracing
RE: K-Bracing
The last time I looked (and I don't use RISA now) I think RISA calculated compression forces in tension only members until a buckling value was achieved. As UcfSE says check the manual, there is an explanation for this.
Regards,
-Mike
RE: K-Bracing
DaveAtkins
RE: K-Bracing
RE: K-Bracing
14159
RE: K-Bracing
RE: K-Bracing
RE: K-Bracing
K-braces will also take aprtion of the gravity load from the beam/girder to which they are connected. Consult your steel design manual for additional information on this aspect of the design. I do not have my copy in front of me at this time, but I believe Jack McCormick's steel design book has a treatment on this topic. Perhaps it is Blodgett's weld design book??
RE: K-Bracing
To elaborate on aggman's post, the true tension only member in RISA-3D takes NO compression, and the Euler member will take compression up to buckling, at which point it fails, so which to use is up to you.
The tension only feature works just fine in RISA-3D, and to my knowledge there is no lack of confidence in it on Risa's part.
There is no reason to hesitate in using them, assuming, as aggman pointed out, you model your structure correctly, but of course that's true for all software.